Current News
Status, November 20th, 2007 - LAST UPDATE
All 32 Science CCDs Imaging thru FIB into SAC.
I am further pleased to announce that today, we finally imaged
all 32 Science CCDs into the SAC#1 through our 8-channel FIB
inter-connect and signal routing board.
As only 1 of the FIB has been built and tested, we imaged the Science
CCDs, 8 at a time through the 8-channel FIB and into the SAC#1
(STARGRASP Array Controller).
The 4 images below show all 32 CCDs being imaged at Room Temperature,
our next Cooldown (#4-) is on hold until we reach a suitable pressure in
the SkyMapper Vacuum Jacket, this is now unlikely to be before next week.
The following data was obtained yesterday afternoon (Mon 20th) and the
data is oriented with the S/M Vacuum Jacket upside-down, CCDs facing
down. So what is termed UPR/LWR bank in the following text is 'as it
looked when reading out' and this is opposite to what the designation
would be were the instrument facing the sky!
(Don't want to cause any confusion!)
4, 8-channel Science CCD Mosaics read out
through FIB and into SAC#1.
SAC #2 side UPR bank of connectors
Tif format image
*MEXT 8 Channel Science CCD R/O FITS data (141Mby)
SAC #2 side LWR bank of connectors
Tif format image
*MEXT 8 Channel Science CCD R/O FITS data (141Mby)
SAC #1 side UPR bank of connectors
Tif format image
*MEXT 8 Channel Science CCD R/O FITS data (141Mby)
SAC #1 side LWR bank of connectors
Tif format image
*MEXT 8 Channel Science CCD R/O FITS data (141Mby)
Close inspection of the last image will reveal that devices 1st and 4th from
the right do not appear to be imaging. The frames are just bias frames.
A test this morning with the ARC 2Chip configuration assembly revealed
the CCDs ARE actually functioning through both of their output ports.
So we appear to have a small anomaly - we know the external hardware
works, it has been rigorously tested and is the same hardware used for
each bank of 8 CCDs. And we know the CCDs are imaging correctly...
so, a small puzzle remains..
Paddy Oates, November 20th. 2007.
Status, November 16th, 2007
All 4 Engineering CCDs Imaging thru FIB into SAC.
I am now pleased to announce that today, we finally imaged the
4 Engineering CCDs, located in the PMFP (see below), through one of
the new Focal plane Interface Board (FIBs) and into the STRAGRASP
Array Controller (SAC#1).
4-channel Eng. CCD R/O through FIB and into SAC.
*MEXT Eng CCD R/O FITS data (70Mby)
This marks yet another very significant milestone in the operation of
the full Science focal plane, which is now awaiting its next cooldown,
(#4-) and connectivity to the 2 SAC 16 channel controllers.
It is planned to interface the current 8-channel system we have been
testing, to the Science Focal Plane, on Monday. This will enble the
science array to be read out, 8 CCDs at a time, into the SAC and under
control of cicada.
Following on from this, as soon as we have the remaining 3 board sets
tested and the Focal plane is at operating temperature, a full 32 CCD
read out can then be undertaken and the system noise performance measured.
Status, November 15th, 2007
First Image retrieved from new FP FIB.
Thursday afternoon, November 15th. The first image was obtained from
one of our E2V MS#02 CCDs (a fully operational 'mechanical sample' CCD)
- taken at Room Temp using the new FIB FP inter-connectivity boards.
This means we are now on track for connecting to our Room Temp. 'Poor
Mans Focal Plane' (this is a 4 Eng CCD rig to allow us to perform
Engineering work, see pictures below) and retrieve images to confirm
the operability of the new hardware.
From there it will be possible to extend the R/O configuration to 8, 16
and 32 devices and so image the true focal plane at Room Temp before
Cooldown#4- proceeds next week.
We are now on the way to having a fully operational focal plane, interfaced
through our new connectivity hardware and for which, subsequently, the
electronics can be optimised to provide the low noise optical
detector focal plane, we have all been working so hard to achieve.
Status, November 9th, 2007
Focal Plane Connected and Working.
Subsequent to the Full population of the Focal Plane, an extensive connectivity
test was performed yesterday (Thurs) which was successfully completed.
Having obtained the external shorting harness yesterday lunch-time,
all 32 detectors were interfaced to their mating Tactics connectors and
then a full Room Temperture Imaging test performed, 2 detectors at a time.
Data being obtained from both the CCDs output amplifiers to verify all was
working.
The RT imaging confirmed the full operation of all devices in the Focal plane
and so around 4pm, the Vacuum pump was connected and pumping of the
instrument commenced. We will now move to Cooldown#3 (the 4th), first thing
Monday morning.
This will be the first thermal cycle with a full complement of Science CCDs
and so is an important step in the Focal Plane characterisation process.
Well done all concerned is what I say!
Status, November 7th, 2007
Focal Plane Populated with E2V Science CCDs.
Cooldown #2C was terminated on Friday November the 2nd in
preparation for this weeks activity....
The 32 Science CCDs were installed during a 9 hour
period yesterday, November 6th.
All the installation work went well and the Focal plane looks
stunning. we have a great instrument.
Two shots of Fully populated Focal Plane.
A full set of pictures can be found
*here*
My thanks to Mike Petkovic who sat and provided support all day and
did the documentation on the installation process so there is now
a formal written record of what I did! Both for the installation
and removal of a device.
In no particular order...
Thanks should also go to Peter Conroy and Andrew Granlund for taking
the E2V CCD installation design and implementing it so well in SkyMapper
and providing a very safe system to work on.
Andre de Gans assembled the Flexes, did all the labelling and cleaning and
the internal wiring harnesses for temp. sensing etc.
Errol Kowald laid out the flex cable design & Samtec panel feedthrough
connectors.
Mike Ellis and Marian Szczepkowski have been and are reposonsible for all
the low noise cabling and focal plane interconnectivity respectively, the
latter of which will be characterised tomorrow and in the next few days.
In the workshop, Col, Robbie and Ross have provided excellent mech.
Eng support and last but not least all those 'hidden folk' in Admin who
make all the big decisions and are after all the most important
folk of all :-8)))
Status, October 3rd, 2007
SkyMapper Focal Plane at Cooldown 2B.
We have pushed along the refit of the focal plane with the modified Invar
plate carrier and some up-dates to the internal mechanical and electrical
arrangements. All this was carried forward over the last few weeks with
the efforts of the Mech., Electronics and Computer Teams here.
Namely Peter Conroy and Andrew Granlund on the Mech. side
Andre de Gans, Marian Szczepkowski and Mike Ellis in Electronics
and Annino Vaccarella in the Computing section.
Overseen and 'encouraged' by our Project Manager, Mike Petkovic.
The Focal plane is now operating once more at temperature (-120C)
to allow me to do some more noise characterisation. We will then be
setting up to interface our new SAC hardware via the FIBs (Focal Plane
Interface Boards) which allow us to inter-connect the CCDs to the SACs
and to then do an end-to-end test with the 2 SAC controllers. This will
now be operated directly with Cicada in either 8, 16 or 32-channel mode,
(see details below for an account of the progress with this aspect).
We are now also in a position to interface 3 devices (1 Mech Sample
and 2 Eng CCDs) via the new FIBs to the 2 SACs at Room Temp.
All this hardware is being proofed at Room Temperature using our
newly contructed 'Poor Mans Focal Plane'. This is the old Invar
plate carrier from the VJ, mounted in a black Pelican box with an
aperture to allow us to mount one of the spare Samtec Connector
carrier plates and connect, via 3 spare flexes, the Mech. Sample #02
and Engineering CCDs #03 & #04 CCDs mounted on the Invar plate,
see the following pictures.
Some pictures of the PMFP!! Assembly.
The following pictures illustrate the installation of the Mechanical
Sample CCD and the 2 Enginnering CCDs into the Invar Carrier plate.
1. Draw bar pulling the 2nd CCD into place,
locating pin just behind the draw bar.
2. 3 CCDs now installed onto the Invar carrier, showing
shorting pads still in place and all ready to go in the Box.
3. Invar Carrier and 3 Detectors in the light tight Pelican Box,
and ready to be brought outside!.
These E2V CCDs image sufficiently well at Room temperature,
using fast pixel sampling (0.2+0.2us), to retrieve images to
confirm the SAC/FIB hardware is working as expected.
This will then give us confidence that we can safely connect to
the $2.5million Science CCDs when they are installed in the Focal plane.
The population of the Focal Plane with the 32 Science CCDs is set to
take place before the end of this month (October 2007).
Status, September 18th, 2007
SkyMapper Focal Plane Imaging Data taken
from STARGRASP in 32-channel mode.
We have just acquired the 1st 32-channel R/O from a single
32-channel SAC and reading direct into Cicada.
Again - we only have 2 CCDs connected and they are in positions
6 and 7 as indicated in the small diagrams below.
Due to the relatively slow pixel sampling (2.5 or 4us) being used at
present, the effects of dark current are swamping the 2 images. We are
attempting to get a faster read-out implemented (0.5-1.0us sampling)
and this should result in us being able to see more of the detector
defects, evem at Room Temp.
The image below shows a 32-channel R/O and this data was taken from
a SINGLE SAC unit with 2, 16 channel Pre-Amp and DACQ cards mounted
in the box.
This setup is different from what we plan to do when the system is
deployed, where we will have 2 SAC boxes, one at either side of Focal
Plane and each housing a single set of 16-channel hardware consisting of
one P/A and one DACQ/FPGA card.
There will be an identical system residing at RSAA acting as a Test bed
and as a 'hot-spare' in case of problems at SSO.
32-channel R/O from a single SAC.
Room Temp. Bias Frame data JPG image
Room Temp. Bias Frame data TIF image
*MEXT Data Cube or Mosaic IRAF FITS data (564Mby)
Status, September 6th, 2007
SkyMapper Focal Plane Imaging Data taken
from STARGRASP in 16-channel mode - WORKING.
We just achieved 16-channel read out from the SAC, see the
image below, which again shows an LED Pre-flash frame,
of 100ms duration with the 2 real detectors in the positions
indicated below in the small table.
Annino Vacarella deserves credit for his persistence with the
Cicada Integration and I would like to thank John Tonry, Peter
Onaka & Sidik Isani at the University of Hawaii for their
excellent design and continued support of our
STARGRASP Controller.
Bank:-DEV#0------------||-DEV#1-----------
--------------------------------------------------
CCD# 01 - 03 - 05 - 07 || 09 - 11 - 13 - 15
CCD# 00 - 02 - 04 - 06 || 08 - 10 - 12 - 14
-------------------------^------------------------active detectors
-------------------------v------------------------
100ms LED Preflash Frame data JPG image
*MEXT Data Cube or Mosaic IRAF FITS data (282Mby)
The mapping of devices has been set so that the images on the
display match the physical location of the devices when we have
the full complement of Science CCDs populating the Focal plane.
The pixel values in the device (Eng. CCD#03) at position #06 range
from a few thousand adu to about 18,000 adu and the pixel values
in the device (Eng CCD#04) at position #07 range from about
18,000 adu to 52,000 adu. These values are consistent with those
found on the ARC Test system and from the fact that device #07
is vertically above device #06 in the focal plane. It is also
nearer the source of the LED light. See following picture:-
Arrangement of Eng. CCDs in Focal plane.
There is also evidence once more of a small amount of X-talk into the
other channels but given that none of the remaing 14 channels are
connected to anything or that the wiring and inter-connectivity hardware
has been finalised, this is not un-expected.
This afternoon we will be procedding with some noise tests and early next
operating both the 16 channel controllers to finally achieve 32-CCD read out.
This work should now procedd without event as the Cicada environment to
operate 32 CCDs is already in place.
Status, September 5th, 2007
SkyMapper Focal Plane Imaging Data taken
from STARGRASP in 8 & 16-channel mode.
We have just achieved Read out of the 2 of the Focal plane Eng CCDs
into the SAC (
STARGRASP Array Controller) under control from CICADA.
The 2 images below show the 8-channel readout out, only 2 CCDs are
connected at the present as we have yet to take delivery of the
2 sets of 2x8 channel SAC to VJ inter-connection boards,
FIB, Focal Plane Interface Boards.
These will allow us to finally read both sets of 16 Science CCDs
when they have been tested and installed.
Block Diagram of the System.
The following image shows a Block diagram of the system illustrating all
the relevant parts of the hardware: SAC #1 & #2, FIBs 1,2,3 & 4 and the
Vacuum Jacket Invar plate.
Pictoral Diagram of the System.
The following image shows a mosaic of pictures fitted together illustrating
how we expect the final system to look. This reflects the components
identified in the block diagram above: The Vacuum Jacket with 4 Engineering
CCDs mounted, the two SAC#1 FIB and the SAC#1 with its temporary front
plane interconnection board which allows connection to any 2 of the 4
Engineering CCDs.
The installation of the 32 Science CCDs is now set for late
October and this operation will take place in the AITC Clean Room.
We may by that stage have set up a Web-cam - so the procedure
can be watched by interested parties... at my discretion!..
In the meantime we are imaging with any 2 of the 4 available Engineering
devices which have now been in the focal plane since the 5th May.
We have therefore maintained the detectors at operating temperature
for some 4.5 months and have seen no adverse effects with the operation
of the focal plane.
1st Image: an 8-channel R/O into Cicada
As can be seen, this is an LED pre-flash (100ms duration) of the CCDs
in the focal plane. We have an ring of LED light sources mounted around
the periphery of the focal plane just on the outside of the window. These
can be pulsed, in the same way I do with the internal LEDs on teh 2 test
dewars.
They are useful as they permit a quick and easy exposure to be taken to
confirm the operation of the complete system.
We can read out only 2 of the 4 available Engineering CCDs at present and
we are currently connected to Eng#03/#04.
The image shows all 8 channels read-out but only the top right-hand and
bottom right-hand image data is real. The other channels contain a small
amount (~0.1%) of X-talk from the 2 live channels.
Of note aew the detector defects - easily seen in the FITS data, and the
X-talk from the defects xcan be seen in the un-loaded (i.e. 'floating')
remaining video channels.
In the JPG image I have pointed the cursor at one of the artefacts on the
CCD surface, to confirm that we really do have the correct data. I have
seen this 'feature' in pre-flash frames taken using the ARC (SDSUIII)
controller when connected to the Focal plane. So all this is real CCD data.
Scroll over to the right to see the 'feature' in the magnified part of the image.
8-Channel, 100ms LED Pre-flash frame
Pre-flash images from from Eng#3 and Eng#4 CCDs at top and bottom right.
100ms LED Preflash Frame data JPG image
*MEXT Data Cube or Mosaic IRAF FITS data (141Mby)
2nd Image: a 16-channel R/O into Cicada
16-Channel, 100ms LED Pre-flash frame
Pre-flash images from from Eng#3 and Eng#4 CCDs, Data is missing!
You will note that the LED pre-flash light, which should now be
located in detector 'panels' 6 and 7, is missing - the data in
these panels looks like Bias.
The data is retrieved in 2 x 8 chip banks, and the arrangement
on the display has been organised so that the appearance matches
how the detectors would appear - looking into the front of the
vacuum jacket. The image data is therefore organised as follows:-
Bank:-DEV#0------------||-DEV#1-----------
--------------------------------------------------
CCD# 01 - 03 - 05 - 07 || 09 - 11 - 13 - 15
CCD# 00 - 02 - 04 - 06 || 08 - 10 - 12 - 14
-------------------------^------------------------active detectors
-------------------------v------------------------
100ms LED Preflash Frame data JPG image
*MEXT Data Cube or Mosaic IRAF FITS data (282Mby)
We are actively seeking the solution to this problem but we
feel we are now very close to having the 16 channel controller
reading out the data correctly.
It is planned that today or tomorrow we will connect the fibre to
the 2nd SAC and we should then be able to retrieve 32 Channel data
straight into Cicada. This _should_ be straight forward as this has
been tested already under simulation. The hardware exists to do all
this - all we have to do is connect it up.
On Friday (7th September) the Focal Plane will be allowed to warm
up over the ensuing weekend, after 4 and a half months at temperature
(155K). This is to permit us to refit the Vacuum Jacket with modified
Invar and Copper plates and do some other engineering tasks.
We hope this work, refittment of the 4 Engineering CCDs and then
pumping and cooling again will be finished by the end of September.
There will then be a final Engineering characterisation phase
before the system is allowed to warm up for the installation of
the 32 E2V Science CCDs towards the 3rd or 4th week in October.
Status, June 21st, 2007
SkyMapper Focal Plane Imaging Data taken
from STARGRASP & E2V Eng#01 & Eng#02 CCDs.
I have just taken images from the Engineering #1 & #2 CCDs in the
SkyMapper focal plane, and read them out into the SAC (STARGRASP
controller) simultaneously - in similar fashion to the way the ARC
reads out the devices in 2Chip mode, as described below.
The imaging capability of the SAC and its and interface to the SkyMapper
Vacuum Jacket has been progressed with the hard work undertaken by
Bernie Keys in the electronics section here at RSAA. He has
continued to provide valuable technical support during this period,
to achieve the 2 CCD R/O from the SAC, into the Test System.
In addition Annino Vaccarella from the computing section
has made a commendable step foreward in providing the read out
environment under control of our front-end detector application,
Cicada. This was achieved today (Thurs 21st) and we can now
read any 2 of the 4 Eng CCDs in the Focal Plane, directly into Cicada
via the SAC controller.
From here we will need to extend this control to 16 channels, by
management of the hardware and software already in place to
achieve this. This is 'work in progress'...
The hard part was to get 1 CCD and then 2, simultaneously
operating; the move to N (16) should pass without event - this
is now being vigorously pursued.
Pictures of the experimental setup are shown below.
1.
2.
- 1. General view of the S/M Instrument showing all the components.
- 2. Detail of the Detector to SAC interconnectivity.
There are a selection of images below, taken using the SAC and connecting
to 2 of the 4 Engineering CCDs currently available in the focal plane.
All images were taken at the operating temperature, T=-110C.
LED Pre-flash frames from 2 CCDs.
10ms LED Pre-flash images from from Eng#1 and Eng#2 CCDs.
10ms LED Preflash Frame data JPG image
*MEXT FITS data (35Mby)
50ms LED Pre-flash images from from Eng#1 and Eng#2 CCDs.
50ms LED Preflash Frame data JPG image
*MEXT FITS data (35Mby)
200ms LED Pre-flash images from from Eng#1 and Eng#2 CCDs.
200ms LED Preflash Frame data JPG image
*MEXT FITS data (35Mby)
Dark Frame Data from 2 CCDs.
3600s Dark frame images from Eng#1 and Eng#2 CCDs. This is an approximate time only,
as we have not implemented an integration timer on the Test system at the present time.
T=-110C, 3600s Dark frame JPG image
*MEXT Fits data (35Mby)
Bias frame images from 2 CCDs.
Zero second Bias images having a sigma (noise) of xxadu from Eng#1 and Eng#2 CCDs.
0sec. Bias frame JPG image
*MEXT FITS data (35Mby)
Pictures of the Pin Hole Test Exposures.
Pin hole image of Colour photograph, stuck to the ceiling of the Pump Room,
imaged on to the ENG#01 & #02 CCDs at the same time. This photograph shows
the origianl members of the SkyMapper team in the Mech. Design demountable
just before the 2005 CDR in August.
15s Pin-Hole image of original Skymapper team JPG image
*MEXT FITS data (35Mby)
15s Pin-Hole image showing affect of water accumulation on
front window JPG image
*MEXT FITS data (35Mby)
Status, May 17th, 2007
SkyMapper Focal Plane Imaging Data taken
from ARC & E2V Eng#01 & Eng#04 CCD.
I have just taken some images from the Engineering #1 & #4 CCD in the
SkyMapper focal plane.
These images were obtained by exposing the detector to light passed through
1 of 4 small pin-holes, sat just above the detectors on the VJ window. The
availabilty of the 4 pin holes means any 2 of the 4 detectors may be so imaged.
To make things easy - our small iris shutter is sat above the appropriate
pin-hole so that timed exposures may be undertaken.
All images were taken at the operating temperature, T=-100C.
The location of the shutter was moved slightly, to more centrally position
over the pin-hole for the 2nd pin hole image. There is some evidence that
the 1st image was vignetetted slightly by the shutter's off-centre position.
Pictures of the Pin Hole Test Exposures.
- 1. Pin hole image of data sheet stuck to the ceiling of the Pump Room,
imaged on to the ENG#01 CCD detector.
- 2. Pin hole image of a photograph of the early SkyMapper Team, again
stuck to the ceiling of the pump room and imaged onto the ENG#01
CCD detector.
- 3. Central section of pin hole image showing the team members,
ENG#01 CCD.
- 4. Pin hole image of a photograph of the early SkyMapper Team, again
stuck to the ceiling of the pump room and imaged onto the ENG#04
CCD detector. The left hand side of the image is Eng#3 CCD which is
a bias frame as there was no light imaged onto this device.
1.
2.
3.
4.
2a. Pin Hole image of early SkyMapper team members Fits data, ENG#01 CCD
4a. Pin Hole image of early SkyMapper team members Fits data, ENG#04 CCD
Status, May 10th, 2007
Data Retrieval from SAC (STARGRASP) to Cicada.
We are now in a position to retrieve CCD data directly from the SAC to Cicada.
At present this is using our Test Dewar#1 with the E2V Mechanical Sample CCD#2,
this a fully operational device and so is useful for this type of Engineering work.
Annino obtained the Test Pattern data yesterday (9th) on the RSAA Test system
using external Temp. servo and manual shutter control, (i.e a switch, Mr. Rimmer)
The image below is a fairly standard looking Test Pattern frame, similar to
the data I have already obtained from this Test Dewar and CCD using the ARC
controller - see details towards the middle of these pages for this data.
The data below shows a 5s Test Pattern frame at T=-110C taken using
our Test Dewar#1 and the SAC controller.
This was all achieved using Cicada and communicating directly with
the SAC (STARGRASP) control hardware.
Test Pattern data JPG image
T=-110C Test Pattern Fits data
SkyMapper Vacuum Jacket Eng. CCD Test Phase
The work to characterise the Engineering detector's performance is underway
in the AITC detector lab. (LG1.12), with the Vacuum Jacket itself located in
the Pump Room (LG1.14), next door.
We have had the focal plane cold, at operating temperature (currently T=-100C)
and I am attempting to measure some formal system parameters, such as
System Gain, Noise, Dark Current, Light Leaks etc.
The two pictures below show the SkyMapper Vacuum Jacket in the pump room,
being cooled ready for detector characterisation.
The second image is a 'Flat-Field' unit we knocked together to do an
independent test of the system Gain. Normally we use a series of LEDs built
into the top of the instrument, above the window and outside the vacuum
environment, to perform this test (these LEDs are located just under the
dark slide seen on top of the instrument in the previous picture (with a
DVM sat on top of it).
As a check, this Flat-Field Unit was used to perform the same measurement as
the standard LED array. The FFU has a small LED at the top of the unit, behind
a Mylar diffusing screen and illuminates the 4 detectors in the focal plane,
which we image, 2 at-a-time.
1.
2.
Status, April 19th, 2007
Dual CCD Operation in Vacuum Jacket.
I am happy to report that since moving the Vacuum Jacket into the
AITC clean room (Room LG1.13), we have been able to progress with
the next stage in the CCD detector work.
This work is being undertaken in stages, and as can be seen below, we
have already proofed out operating 2 CCDs from our controller at any one
time in the 2 independent RSAA Test Dewars. These had a single E2V CCD
mounted and interfaced to the ARC controller, being read-out through a single
amplifier each and the image combined to make it look like a single, 4kx4k
'Super-CCD'.
This was undertaken to allow us to migrate the arrangement to the SkyMapper
Vacuum Jacket and install the 4 E2V Engineering CCDs and repeat the process,
this time at room temperature (see images below) and at operating temperature.
This work will give us a first indication that the internal arrangement of
thermal paths and electronics permit CCD operation in a low-noise environment.
To facilitate this we are able to select any 2 devices from the 4 available,
these now located in the focal plane, resulting in a total combination
of any 2 devices from 6; each pair of which may therefore be formed into
a single, 4kx4k, 'Super-CCD'
Pictures of the Engineering CCD Installation.
- 1. 4 Flex Connectors being tested for signal levels.
- 2. 1st CCD being raised into Focal plane.
- 3. 2 CCDs in Focal Plane
- 4. 4 Flexes attached to 4 Engineering CCDs.
- 5. External Connectivity for 2 CCDs, other 2 grounded
- 6. 4 CCDs in Focal Plane, ready for Room Temperature Imaging
1.
2.
3.
4.
5.
6.
Detector Lab. Pictures.
A full set of pictures showing the SkyMapper Vacuum Jacket being operated in the
AITC Detector Lab. (Room LG1.12 for the un-initiated!) at Room Temperature,
can be found
*1.here*
Clean Room Installation Pictures.
The full set of pictures relating to the installation & integration of the
Eng. CCDs into the SkyMapper Vacuum Jacket can be found
*2.here*
The Engineering CCDs - Room Temperature Data
1. Engineering #1 & #2 - 'Super CCD' JPG image
Eng#1 & #2 Room Temp Fits data
2. Engineering #1 & #3 - 'Super CCD' JPG image
Eng#1 & #3 Room Temp Fits data
3. Engineering #1 & #4 - 'Super CCD' JPG image
Eng#1 & #4 Room Temp Fits data
4. Engineering #2 & #3 - 'Super CCD' JPG image
Eng#2 & #3 Room Temp Fits data
5. Engineering #2 & #4 - 'Super CCD' JPG image
Eng#2 & #4 Room Temp Fits data
6. Engineering #3 & #4 - 'Super CCD' JPG image
Eng#3 & #4 Room Temp Fits data
Status, April 10th, 2007
STARGRASP Read noise and dark frame data.
The latest run with the E2V Mech.Sample CCD#1 running on the SAC was used
to obtain the following data from the CCD at an operating temperature of T=-110C
ARC Controller
- 1+1us sampling, system gain 0.97e/adu & 0.97e/adu.
- 7e & 4.5e rms for the left & right-hand amplifiers respectively.
- Dark Current = 3.4e/pix/hour.
- Read out time, ~40 secs, single port.
SAC Controller
- 1x4 us signal sampling, system gain 0.84e & 1.14e/adu
- 24e & 6.5e rms for the Right amplifier only.
- Dark Current = 5.7e/pix/hour.
- Read out time, ~20secs, single port.
Status, April 2nd, 2007
STARGRASP Imaging E2V CCD Test Pattern Data.
An Image of our standard Test Pattern frame has just been obtained with
the SAC and our Test Dewar#2.
The CCD is almost at operating Temp. (T=-110C)
and the 5 sec Test Pattern frame was obtained by the following sequence of
commands on the controllers specified.
(a bit of a hotch potch of a way to do it - but it works!)
- clean ; clean ; clean (on SAC)
- Open Shutter (on ARC)
- Wait 5 seconds
- Close Shutter (on ARC)
- readout (on SAC)
- transfer data frame to host (SAC to Sun)
where
'clean' clears out the ccd of residual charge and
'readout' reads the charge from the detector into memory.
The data fame below show a 5s Test Pattern frame at T=-110C taken by
the SAC controller using our Test Dewar#2 and the ARC controller to
servo temperature and operate the shutter.
Test Pattern data JPG image
T=-110C Test Pattern Fits data
The following pictures, again show the experimental arrangement.
1.
2.
3.
4.
STARGRASP Imaging E2V CCD in RSAA Test Dewar at RT.
A Room Temp Read-out was achieved on Friday from our E2V
Mech. Sample #2 CCD mounted in our own RSAA Test Dewar
(#2, the dewar normally used for WiFeS CCD evaluation).
This now means we can proceed to a cold test and evaluate the system
noise based on a dewar and wiring of our own building. This will be
the first step in us confirming we can operate the SAC with a known
low-noise system and achieve low read-noise and other science performance
parameters which are demanded by the SkyMapper Science goals.
The Templeton dewar, which belongs to the University of Hawaii (UofH)
can now therefore be returned to them, where further development work
will proceed to finish off the final design of the hardware.
The following pictures show the experimental arrangement.
1.
2.
3.
4.
The data fames below show room temperature & T=0C read-out of our
E2V MS#2 CCD, mounted in the RSAA Test Dewar#2 and operating on
the STARGRASP Array Controller (SAC).
Click Image for JPG data...
1.T=RT Fits data
2.T=0C Fits data
The data below shows a room temperature read-out of our
E2V MS#2 CCD, mounted in the RSAA Test Dewar#2 and
operating on Bob Leach's CCD Controller (ARC)
MS#2, O/P amp(L) on ARC, JPG image of RT readout.
MS#2, O/P amp(L), on ARC, RT readout, Fits data. (17Mby).
Status, March 22nd, 2007
ARC Controller Imaging 2 E2V CCDs at RT.
A Room Temp Read-out, from 2 independent E2V CCDs, each one
mounted in a separate Test dewar, has just been achieved in
the detector lab.
The detectors are interfaced via their flex cables, hanging outside the front
of the dewar in a 'heath-robinson' arrangement, through a custom controller
cable, constructed by Bernie Keys, to a dual channel ARC controller.
The following pictures show the experimental arrangement.
1.
2.
3.
4.
5.
6.
Two RSAA Test Dewars used in experimental setup to perform Dual CCD R/O
The ARC controller, in this mode, is acting as if there was a single CCD,
split R/O in progress. The images are at Room Temp., but identifiable
features can be seen on both the Eng#1 CCD on the Left amp (TD#1) and
the Mech. Sample#2 CCD on the Right amp. (TD#2).
The final image shows the Room Temperture readout which, at 0.5us signal
sampling, takes 30secs to readout the pseudo 4kx4k pixel detector!!
Eng#1, O/P amp(L) & MS#2, O/P amp(R) JPG image of RT readout.
Eng#1, O/P amp(L) & MS#2, O/P amp(R), RT readout, Fits data. (33Mby).
Another Significant Milestone.
So we now have a viable means of testing the vacuum jacket detector
connectivity - albeit only through 2 channels at a time, at present.
We will however get sensible results at Room Temperature, if the devices
are in the dark, and this will hence mean cutting an awful lot of time
out of doing the work if we had to cold cycle the system each time
we re-configured the CCDs for evaluation purposes.
Status, March 14th, 2007
STARGRASP Array Controller Dark Frame & Noise.
I now have some noise measurements from SAC and a 1537 second
dark frame.
The dark frame data was obtained at a temperature of T=-128C and the
temperature was measured by temporarily switching back to the ARC controller!
Measured Dark Current for this device during the 1537s exposure
System Gain = 1.046e/adu
Mean Dark Signal = 137 adu
Mean Bias in Y-overscan = 135 adu
Net dark signal ~2adu in 1537s => 5e/pix/hour
This is a little high, but there IS evidence that the dewar is leaking
light, maybe through the glue used to hold the Beryllium window in place.
Mech. Sample CCD#1Output Amp(L) JPG image of 1537s Dark frame.
Output (L) R/O Dark frame Fits data at T=-128C (17Mby).
Amplifier Noise measurements taken for Mech. Sample CCD#1
Data was taken for both the ARC and SAC controllers.
ARC Controller
- 1us sampling (system gain 0.85e/adu & 0.925e/adu)
- 4.2e & 4.7e rms for the left & right-hand amplifiers respectively.
SAC Controller
- 1+1us signal sampling (system gain 1.05e/adu)
- 5.6e rms for the Right amplifier only.
Status, March 13th, 2007
STARGRASP Array Controller Imaging CCD Cold.
I have the detector going cold now and have just taken the LED
pre-flash image shown in the link below.
Although I am not sure yet how to tell what the Temperature is, it's still
quite a bit away from operating temperature.
LED Pre-flash Data
I already have a pre-flash frame using the internal dewar LEDs in Templeton,
from our own test system, the data from which is available below. This data
was taken when the Templeton Dewar was here last August and was operating
on our ARC Controller based Test system. See the link:-
*Templeton/ARC PF frame*
And here is the current data - taken 10 minutes ago at a Temp=-85C (measured
using the ARC controller).
Mech. Sample CCD#1Output Amp(L) JPG image of Pre-flash at T=-85C.
Output (L) R/O Pre-flash FITS data at T=-85C (17Mby).
And a 2nd frame at T=-100C.
The defects - seen in the Frame taken last August at T=-120C, on our own
Test system, can now be clearly seen.
Mech. Sample CCD#1Output Amp(L) JPG image of Pre-flash at T=-100C.
Output (L) R/O Pre-flash FITS data at T=-100C (17Mby).
CDD Bias Frame Data
And here, a Bias frame, taken at a
temperature of -90C. The split in the serial
register can be clearly seen, as again, can the X under and over-scans.
Mech. Sample CCD#1Output Amp(L) JPG image of Intermediate Temp. Bias frame.
Output (L) R/O Intermediate Temp. Bias frame FITS data (17Mby).
STARGRASP Array Controller Imaging CCD.
I have just taken the first two images at Room Temperature from the
new STARGRASP Array Controller (SAC).
The 2 CCD images I have look nominal - you can see the X-under and
X-overscans clearly and there is a lot of dark signal on the frame -
as expected. This data can be compared with similar images from our
own Test System, lower down these pages..
Mech. Sample CCD#1Output Amp(L) JPG image of Room Temp Bias.
Output (L) R/O Room Temp Bias frame FITS data (17Mby).
As can be seen - this image is assymetric - the frame size having been set to
dx=2200 by dy=4400. This is slightly different to the one I use here, which is
dx=2148 by dy=4200. The assymetry results from the serial shift register
being over-scanned by 2200-2148 = 52, which are hence virtual pixels. In
similar fashion to the vertical over scan which has 4400-4096 = 304 virtual
pixels (but not seen here due to the elevated dark current arising from the
Temperature at which this frame was obtained.
The Templeton Dewar was pumped last night and today I will obtain some images
with the detector cold. As the Beryllium window is still fitted - no external
imaging is possible but I plan to remove this tomorrow and replace with the
standard glass window so that I can image some test pattern data etc...
Status, March 8th, 2007
STARGRASP Array Controller now at RSAA.
The University of Hawaii's STARGRASP Array Controller (SAC) was delivered to
RSAA on Monday March 4th. See
STARGRASP Page
for details of this new generation of Array Controller.
This hardware is to drive the 32 CCD Focal Plane Array in SkyMapper and we
have now taken full delivery of the complete system.
The heart of this system consists of 3, 16-channel CCD (DACQ/PA/FPGA) CCD
read-out boards, 2 of which will be used as the Array Controllers for the
32 E2V CCD Mosaic for SkyMapper.
The other 16-channel system will remain at RSAA as a Test system and hot spare.
The following pictures show the SAC hardware on one of the benches in the
detector lab.
1. STARGRASP - General View of Kit
2. STARGRASP- Network Switch & Templeton Dewar
3. STARGRASP - Pixel Server and the Dual Agilent PSUs
4. STARGRASP- Compaq Laptop, SAC (side) & Templeton showing Beryllium Window
Looking clockwise from the front right side-
- the large (& heavy) dual agilent power supplies (for the Test System only)
- A linux based 'pixel server' (281.5 million pixels - to be read out ~20s)
- Compaq Notebook to run the Test system 'demo version'
- Chassis containing the 3, 16 channel DACQ/PA and FPGA boards.
- A Dell PowerConnect, 24-channel Ethernet Switch
- A fibre to Ethernet media converter
- at the rear - the UofH "Templeton' CCD dewar, housing one of our Operating Mech. Sample CCDs
I have today (8th), finally got the Australain version of DC supplies and AC
cabling to be able to power up the system in 'demo' mode. This mode is to allow us
to operate the Templeton Dewar (see details of this, lower down the page) with
one of our Mechanical Sample CCDs.
I should be able to get, at least, room temperature images form the detector by
either late this afternoon or early next week.
Work with this new system at the moment revolves round (carefully) following the
'idiots' guide to cabling and powering up the hardware. It is hoped that either
today (Thurs) or early next week, a room temperature image can be obtained from
the Mechanical Sample E2V CCD housed in the Templeton Dewar.
This dewar, sent to us from the UofH last August, was equipped with MS E2V CCD and
operated on our ARC Test System here before being returned to the UofH, for them
to integrate the dewar into the new STARGRASP system.
The next step after this will be to operate the Templeton dewar cold, so that some
noise measurements can be taken at our operating temperature (now 170K). We will
then interface the SAC to one of our SkyMapper Test dewar, so that the Templeton
dewar, minus our CCD and assembly, can be returned to the UofH.
Some additional steps will be needed to get us from this position, to operating
the whole 32 CCD focal plane, namely, the interface hardware from the SAC to the
Focal Plane. This work is in an advanced stage of development, but will need testing.
The initial testing phase will be undertaken with 2 of the Eng CCDs, on the bench,
and then mounted in the vacuum jacket, with our 2-channel ARC controller. This will
be followed, it is hoped, by a similar configuration with the SAC
hardware.
If all this goes well, we will then be on track for interface of the SAC to the
formal 32 CCD SkyMapper Focal plane and the real fun will begin!.
Status, December 5th, 2006
Summary of Science CCD Work to date.
The set of links below are pointers to the relevant parts of this page which
report the characterisation data for each of the 4 science CCDs tested and the
order in which they were characterised, the most recent at the end of the list.
Status, December 5th, 2006
Characterisation Data for 4th E2V Science CCD
(05255-02-02, BATCH#5)
This is the last of the 4 SkyMapper CCDs selected for characterisation
and this work was completed today (Tuesday 5th Dec).
and therefore means the Science CCD quantification is now complete.
There are however one or 2 more measurements I would like to make,
which can be scheduled at any time - with one of the Engineering CCDs.
- I would like to obtain some indication of what the red fringing is like -
this should be low, 0.1-0.2%.
- I would also like to assess the H & VCTE from the frames I have available,
for one or 2 of the devices already tested.
Data for the SkyMapper Science CCD#25 was obtained this week,
along with a complete spectral response measurement.
This data consists of a measure of the 2 amplifier noises, a long exposure dark frame,
a QE curve and a pre-flash frame showing some pixel defects, and a standard test pattern
frame.
In addition I have also archived Test Pattern, Pin-Hole and Preflash data for:-
- Binned - 1x2, 2x1 & 2x2. Left & Right amps
- Windowed dx=1500xdy=1500 @ x=1074, y=2000. Left & Right amps
This data has also been archived for the other 2 Science CCDs,
described below on these pages.
All detector data for SkyMapper & WiFeS,
all 3 SII CCD systems - Imager, DBS Blue and Red,
& and all other miscellaneous systems (WFI, Tek)
is available on one of the system shares:-
/priv/samba2/ccd_data/
This device has ~500 dark pixel defects (reported in E2V's test data),
and this time are located throughout the array.
The device specs are again within the contract defect spec. for dark pixels.
This device was selected as it was the only part delivered form BAtch #5.
Again this device exhibits characteristics either meeting or exceeding the contract
spec. we had in place with E2V for all the science CCDs.
10,000s Dark Exposure.
An 10000s dark frame was obtained at the the SkyMapper set point operating
temperature of T=-120C for the Science CCD #25.
The dark frame shows a wealth of CREs (Cosmic Ray Events) and, as usual, some of
them have very long tails.
The frame was taken with the blanking cap on the front of the Test dewar (#1).
This ensures that no extraneous light can enter the window and affect
the measurement of the dark current. This frame was taken using output amplifier
B (op(R))
Measured Dark Current for this device during the 10,000s exposure
System Gain = 0.88e/adu
Mean Dark Signal = 1667.39 adu
Mean Bias in Y-overscan = 1666.13 adu
Net dark signal ~1.26adu in 10,000s => 0.4e/pix/hour
Sci. CCD #25 Ouput Amp(R) JPG image of 10,000s dark frame.
Output (R) R/O 10,000s Dark frame FITS data (17Mby).
Artefacts seen in dark exposures and Flat Field data for this CCD
This device has no column defects and only ~500 dark pixel defects which this time
are spread over the whole image area.
Again all these characterstics are well within the contract spec. for these devices.
10ms LED preflash frame showing CCD pixel defects.
Sci. CCD #25Right-hand R/O JPG image of 10ms LED Pre-flash frame.
Right-hand R/O 10ms LED Pre-flash frame FITS data (17Mby).
1s Test Pattern exposure on Test Box.
The image below shows a standard test pattern exposure from the Science CCD,
mounted on the Test System. Vignetting, due to the shutter can be clearly seen.
Sci. CCD #25 Right-hand R/O JPG image of 1s Test Pattern image.
Right-Hand R/O 1s Test Pattern image FITS data (17Mby).
Spectral Response (QE) data taken for Science CCD #25
The curve below illustrates the spectral response for the Science CCD #25,
measured on the Test system on the 4th of December.
As can be seen, the response again appears very good right across the optical band
from 350nm out to 1050nm. There do however appear to be 3 discrepancies between
the RSAA measuremts and E2V's at 350nm, 500nm and 650nm.
Spectral Response of E2V Science CCD#25.
Amplifier Noise measurements taken for Science CCD #25
The following data confirms the read noise meets the noise spec. for the
SkyMapper Science requirements and is similar for both output amplifiers.
Data was taken for 1us and 2us signal sampling with what is estimated to be
~1e rms system noise in these figures.
- 1us sampling (system gain 0.92e/adu & 0.88e/adu)
- 3.75e & 4.8e rms for the left & right-hand amplifiers respectively.
- 2us sampling (system gain 0.464e/adu & 0.46e/adu)
- 3e & 3.4e rms for the left & right-hand amplifiers respectively.
There is also
~1e rms of system noise included in these figures,
so the devices are performing well and to spec. at the read-out rates used.
Status, November 28th, 2006
Characterisation Data for 3rd E2V Science CCD
(05163-16-02, BATCH#3)
Data for the SkyMapper Science CCD#21 was obtained last week,
followed this week by a complete spectral response measurement.
This data consists of a measure of the 2 amplifier noises, a long exposure dark frame,
a QE curve and a pre-flash frame showing some pixel defects, and a standard test pattern
frame.
In addition I have also archived Test Pattern, Pin-Hole and Preflash data for:-
- Binned - 1x2, 2x1 & 2x2. Left & Right amps
- Windowed dx=1500xdy=1500 @ x=1074, y=2000. Left & Right amps
This data has also been archived for the other 2 Science CCDs,
described below on these pages.
All detector data for SkyMapper & WiFeS,
all 3 SII CCD systems - Imager, DBS Blue and Red,
& and all other miscellaneous systems (WFI, Tek)
is available on one of the system shares:-
/export/samba2/ccd_data/
For this device many (~600) of the 1376 dark pixel defects (reported in E2V's test
data, are located in one position - see the low level preflash frame and a magnified
image of the area below.
The device specs are however within the contract defect spec. for dark pixels and it
will be up to us to decide where, in the focal plane, this device will reside.
This device was selected as it exhibited this large (relatively speaking,
of course) number of defects amongst the 32 science devices we have now received,
the E2V Contract now being essentially complete.
Again this device exhibits characteristics either meeting or exceeding the contract
spec. we had in place with E2V for all the science CCDs.
It is now planned to continue the work and characterise 1 more device from the last
batch (#5). I intend to complete this in the next 2 weeks so all the characterisation
will be complete before Xmas.
The Batch numbers of the CCDs are indicated in the small 'colour' table below and
shown in the CCD directory spreadsheet below.
E2V Test Data for all E2V SkyMapper CCDs
& RSAA Test Data for devices #12, #23 & #21
The link
*E2V Test Data*
references the
*latest* E2V Detector Directory -
a table listing all E2V data and the sampled RSAA data.
8,000s Dark Exposure.
An 8000s dark frame was obtained at the the SkyMapper set point operating
temperature of T=-120C for the Science CCD #21.
The dark frame shows a wealth of CREs (Cosmic Ray Events) and, as usual, some of
them have very long tails.
The frame was taken with the blanking cap on the front of the Test dewar (#1).
This ensures that no extraneous light can enter the window and affect
the measurement of the dark current. This frame was taken using output amplifier
A (op(L))
Measured Dark Current for this device during the 8,000s exposure
System Gain = 0.9 e/adu
Mean Dark Signal=1455.7 adu
Mean Bias in Y-overscan =1454.4 adu
Net dark signal ~1.3adu in 8,000s => 0.53e/pix/hour
Sci. CCD #21 Ouput Amp(L) JPG image of 8,000s dark frame.
Output (L) R/O 8,000s Dark frame FITS data (17Mby).
Artefacts seen in dark exposures and Flat Field data for this CCD
This device has no column defects but a multitude (~600) dark pixel defects over
on the left hand side of the image.
All these characterstics are well within the contract spec. for these devices.
10ms LED preflash frame showing CCD pixel defects.
Sci. CCD #21Left-hand R/O JPG image of 10ms LED Pre-flash frame.
Left-hand R/O 10ms LED Pre-flash frame FITS data (17Mby).
This is a magnified part of the FITS image showing the cluster of ~600 dark pixels
over on the left-hand side of the image.
Sci. CCD #21Split R/O - part of the image.
Image magnified to show the dark pixel cluster on the left hand side better.
1s Test Pattern exposure on Test Box.
The image below shows a standard test pattern exposure from the Science CCD,
mounted on the Test System. Vignetting, due to the shutter can be clearly seen.
Sci. CCD #21 Split R/O JPG image of 1s Test Pattern image.
Left-Hand R/O 1s Test Pattern image FITS data (17Mby).
Spectral Response (QE) data taken for Science CCD #21
The curve below illustrates the spectral response for the Science CCD #21,
measured on the Test system yesterday (Nov. 27th)
As can be seen, the response again appears very good right across the optical band
from 350nm out to 1050nm.
Spectral Response of E2V Science CCD#21.
Amplifier Noise measurements taken for Science CCD #21
The following data confirms the read noise meets the noise spec. for the
SkyMapper Science requirements and is similar for both output amplifiers.
Data was taken for 1us and 2us signal sampling with what is estimated to be
~1e rms system noise in these figures.
- 1us sampling (system gain 0.975e/adu & 0.88e/adu)
- 5.9e & 4.2e rms for the left & right-hand amplifiers respectively.
- 2us sampling (system gain 0.474e/adu & 0.45e/adu)
- 4e & 3.6e rms for the left & right-hand amplifiers respectively.
There is also
~1e rms of system noise included in these figures,
so the devices are performing well and to spec. at the read-out rates used.
Status, November 14th, 2006
SkyMapper E2V Science Device #21 installed in Test System
(05163-16-02, BATCH#3)
All data reported by E2V, along with a complete QE data set
for the 32 science devices is now at the link below.
Today I have removed device #23 from the Test Dewar and installed the 3rd of
the E2V SkyMapper Science CCDs, #21. 05163-16-02, a device from
BATCH #3.
This was selected as
(1) it is a device from a dfferent batch to the 1st 2 tested,
(2) it has a high mid-band QE and
(3) it has the highest number of single dark pixel defects.
Status, November 13th, 2006
Final E2V CCD Delivery #10,
Final 6 Science CCDs arrive at RSAA.
I have just received the 10th delivery from E2V - 6 devices and this marks
the end of the contract with E2V for Science CCDs for SkyMapper.
The data from E2V for all the suite of devices is
in the accompanying spread sheet.
E2V and RSAA Test Data for all E2V SkyMapper CCDs
The link
*E2V Test Data*
references the
*latest* E2V Detector Directory -
a table listing all the devices for the SkyMapper Focal Plane.
Spectral Response Measurements for all 32 E2V SkyMapper CCDs
The following plot illustrates the Spectral response of all the Science CCDs,
shown together for comaprison.
Spectral Response of all SkyMapper CCDs.
Status, November 8th, 2006
E2V CCD Delivery #9, 05163-07-02
Last but one batch, 1 Science CCD arrives at RSAA.
I have just received the 9th delivery from E2V - a single Science CCD.
The data from E2V for this device and both science devices so far characterised
at RSAA are in the accompanying spread sheet.
Again another very commendable device from E2V
E2V and RSAA Test Data for all E2V SkyMapper CCDs
The link
*E2V Test Data*
references the
*latest* E2V Detector Directory -
a table listing all the devices we have to date, i.e. data
for the 26 science devices, and for all 4 of the Engineering
CCDs, the latter data having been obtained on the RSAA Test System.
Spectral Response Measurements for all current E2V SkyMapper CCDs
The following plot illustrates the Spectral response of all 26 Science CCDs,
shown together for comaprison.
Spectral Response of all 26 E2V CCDs currently(08/11/2006) at RSAA.
Status, November 2nd, 2006
Characterisation Data for 2nd E2V Science CCD
(05191-02-01, BATCH#1)
The first set of data for the SkyMapper Science CCD#23 has been obtained this week.
This data consists of a measure of the amplifier noise, some long exposure dark frames,
a QE curve and a pre-flash frame showing some pixel defects.
This device was selected as it exhibited the next worse (relatively speaking, of course)
defects amongst the 25 science devices we have received to date.
This device exhibits characteristics either meeting or exceeding the contract spec. we have
in place with E2V for all the science CCDs.
It is now planned to continue the work and characterise 1 device from each of the
4 batches we have to date. I have colour coded these - for my own convenience only
as follows:-
- BATCH#1
- BATCH#2 - none
- BATCH#3
- BATCH#4
- BATCH#5
10,000s Dark Exposure.
An 10000s dark frame was obtained at the the SkyMapper set point operating
temperature of T=-120C for the Science CCD #23.
The dark frame shows a wealth of CREs (Cosmic Ray Events) and, as usual, some of
them have very long tails. As was mentioned before, the long-tail events are
due to the deeper depleted silicon material used for the SkyMapper E2V CCDs.
Due to the increased size of the depleted region, this material is able to trap more red
photons and hence provide a higher red QE.
The down-side is the presence of many long-tailed CRE events.
The frame below is a 10000s dark frame taken with the blanking cap on the front of the
Test dewar (#1). This ensures that no extraneous light can enter the window and affect
the measurement of the dark current.
This frame was taken using output amplifier A (op(L)) and so there is no bias shift which
occurs when using split serial mode.
Measured Dark Current for this device during the 10,000s exposure
System Gain = 0.88 e/adu
Mean Dark Signal=1412.6 adu
Mean Bias in Y-overscan =1411.0 adu
Net dark signal ~1.6adu in 10,000s => 0.5e/pix/hour
Sci. CCD #23 Ouput Amp(L) JPG image of 10,000s dark frame.
Output (L) R/O 10,000s Dark frame FITS data (17Mby).
Artefacts seen in dark exposures and Flat Field data for this CCD
This device has no column defects and there are 2 pixel traps.
In addition there are 702 white and 255 dark pixel defects.
All these characterstics are well within the contract spec. for these devices.
The pre-flash frames are taken by utilising the internal dewar LEDs, these LEDs can be
pulsed after clearing the detector and just prior to read-out. They therefore provide
a means of calibrating the detector and can also be used to provide signal to inspect
any defects which may be present on the detector. The illumination in this instance,
ought really to be flat, but for calibration purposes it is _more_ useful to have a
non-uniform illumination.
10ms LED preflash frame showing CCD artefacts.
Sci. CCD #23Left-hand R/O JPG image of 10ms LED Pre-flash frame.
Left-hand R/O 10ms LED Pre-flash frame FITS data (17Mby).
3s Test Pattern exposure on Test Box.
The image below shows a standard test pattern exposure from the Science CCD,
mounted on the Test System. Vignetting, due to the shutter can be clearly seen.
Sci. CCD #23 Left-Hand R/O JPG image of 2s Test Pattern image.
Left-Hand R/O 2s Test Pattern image FITS data (17Mby).
Spectral Response (QE) data taken for Science CCD #23
The curve below illustrates the spectral response for the Science CCD #23,
measured on the Test system yesterday (Nov. 1st)
As can be seen, the response again appears very good right across the optical band
from 350nm out to 1050nm and approaches 100% QE in mid-band.
Spectral Response of E2V Science CCD#23.
Amplifier Noise measurements taken for Science CCD #23
The following data confirms the read noise meets the noise spec. for the
SkyMapper Science requirements and is similar for both output amplifiers.
Data was taken for 1us and 2us signal sampling with what is estimated to be
~1e rms system noise in these figures.
- 1us sampling (system gain 0.88e/adu & 0.804e/adu)
- 4.9e & 3.68e rms for the left & right-hand amplifiers respectively.
- 2us sampling (system gain 0.44e/adu & 0.435e/adu)
- 3.3e & 3e rms for the left & right-hand amplifiers respectively.
There is also
~1e rms of system noise included in these figures,
so the devices are performing well and to spec. at the read-out rates used.
Status, October 30th, 2006
SkyMapper E2V Science Device #23 installed in Test System
A week or so has been spent attempting to measure night sky emission lines to see if
I could detect fringing on the Mech. Sample#2 CCD. As these are deep depletion devices
we do not expect anywhere near the level of fringing, seen on undepleted devices. On
these devices the fringes can be as much as 30% in the Red. See the fringing picture for
the 2.3m Imager on the Imager web-page.
On deep depletion devices the fringing is expected to be only ~0.1-0.2%
This experiment was unsuccessful due to to some vagaries of the experimental setup.
I plan to repeat this later, possibly with a Science CCD, now I understand what was
going on.
So, today I have installed the 2nd of the E2V SkyMapper Science CCDs,
#23. 05191-02-01
This was selected as
(1) it is a device from a different batch to the 1st device tested
(2) It has the highest mid-band QE of all the devices we have to date
(3) it shows some cosmetic defects including 2 traps but no column defects.
At this stage it is therefore planned to test one device from each of the 4 batches
(1,3,4 & 5) we have available. The Batch number represents a 'wafer run' on the E2V
Fab. (fabrication) line and hence represesnts what might be considered different
families of devices which just may exhibit slightly differing characteristics.
Though from the E2V data - these differences look to be minimal.
Status, October 19th, 2006
STARGRASP controller Images E2V CCD
I am very happy to report that the Pan-STARRS (STARGRASP) controller,
developed and built by John Tonry and Peter Onaka at the University of
Hawaii, has just produced its first test images from the detector we supplied
to them in one of their own dewars.
The link
*Templton Test Dewar*
illustrates the work we did to enable John's group to interface our device
with the STARGRASP controllers. This has entailed the Pan-STARRS group
constructing a test version of the controller, fabricatiing the custom cables
and generating suitable read-out code for this device.
THIS IS A VERY SIGNIFICANT STEP FORWARD.
See
STARGRASP Page
for the first of 2 test images taken with the new controller and the E2V CCD.
JPG image of the 1st data from the STARGRASP controller
Mech. Sample#1 CCD & STARGRASP
A test pattern image just obtained on the STARGRASP controller.
Image data of a similar pattern from our own Test system
The image below shows a similar test pattern exposure from the
Engineering CCD#4, mounted on our own Test System.
Vignetting, due to the shutter can be clearly seen.
Eng. CCD #4 Right-hand R/O JPG image of 3s Test Pattern image.
Right-hand R/O 3s Test Pattern image FITS data (17Mby).
Status, October 11th, 2006
E2V CCD Delivery #8,
Latest batch of 3 Science CCDs arrive at RSAA.
I have just taken delivery of the 8th batch of Science CCDs for the
SkyMapper Focal plane. Again - some of the charactersitics are superb,
one device achieving almost 100% QE at 500nm!
Again another very commendable batch of devices from E2V
E2V and RSAA Test Data for all E2V SkyMapper CCDs
The link
*E2V Test Data*
references the
*latest* E2V Detector Directory -
a table listing all the devices we have to date, i.e. data
for the 25 science devices, and for all 4 of the Engineering
CCDs, the latter data having been obtained on the RSAA Test System.
As can be seen, the data from the latest science devices shows some
very respectable peak and one quite high UV response.
Spectral Response Measurements for all current E2V SkyMapper CCDs
The following plot illustrates the Spectral response of all 25 Science CCDs,
shown together for comaprison. Data between the points has been interpolated
by the Excel spreadsheet program.
Spectral Response of all 25 E2V CCDs currently(11/10/2006) at RSAA.
2nd Science device characterisation to start next week
Science device #15, the next in line exhibiting the highest level of defects of the
science complement will be installed in the Test system next week.
The formal characterisation will then proceed and a futher 2 devices investigated.
Currently it is planned to look at 4 in total of the 32 science devices.
Status, October 3rd, 2006
Characterisation Data for first E2V Science CCD
(04484-10-02, BATCH#4)
The first set of data for the SkyMapper Science CCD#12 was obtained last week.
This data consists of a measure of the amplifier noise, some long exposure dark frames,
a QE curve and a pre-flash frame showing some pixel defects.
This device was selected as it exhibited the worse (relatively speaking, of course) defects
amongst the 22 science devices we have recived to date.
This device exhibits characteristics either meeting or exceeding the contract spec. we have
in place with E2V for all the science CCDs
10,000s Dark Exposure.
An 10000s dark frame was obtained at the the SkyMapper set point operating
temperature of T=-120C for the Science CCD #12.
The dark frame shows a wealth of CREs (Cosmic Ray Events) and, as usual, some of
them have very long tails. As was mentioned before, the long-tail events are
due to the deeper depleted silicon material used for the SkyMapper E2V CCDs.
Due to the increased size of the depleted region, this material is able to trap more red
photons and hence provide a higher red QE.
The down-side is the presence of many long-tailed CRE events.
The frame below is a 10,000s dark frame taken with the blanking cap on the front of the
Test dewar (#1). This ensures that no extraneous light can enter the window and affect
the measurement of the dark current.
This frame was taken using output amplifier B (op(R)) and so there is no bias shift which
occurs when using split serial mode.
Measured Dark Current for this device during the 10,000s exposure
System Gain = 0.9 e/adu
Mean Dark Signal=1769 adu
Mean Bias in Y-overscan =1765 adu
Net dark signal ~4 adu = 1.4adu/hour = 1.3e/pix in 3600s
Sci. CCD #12 Ouput Amp(R) JPG image of 10,000s dark frame.
Output (R) R/O 10,000s Dark frame FITS data (17Mby).
Artefacts seen in dark exposures and Flat Field data for this CCD
This device has a column defect which can be seen in the Dark frame.
There are also 3 traps - though I can only find 2! and about 4000 white pixels.
The column defect is affecting the CTE at this point to such an extent that there
is charge trailing into the Vertical overscan.
These artefacts can also be seen in pre-flash or flat-field images.
All these characterstics are well within the contract spec. for these devices.
The pre-flash frames are taken by utilisoing the internal dewar LEDs, these LEDs can be
pulsed after clearing the detector and just prior to read-out. They therefore provide
a means of calibrating the detector and can also be used to provide signal to inspect
any defects which may be present on the detector. The illumination in this instance,
ought really to be flat, but for calibration purposes it is _more_ useful to have a
non-uniform illumination.
10ms LED preflash frame showing CCD artefacts.
Sci. CCD #12 Left-hand R/O JPG image of 10ms LED Pre-flash frame.
Left-hand R/O 10ms LED Pre-flash frame FITS data (17Mby).
3s Test Pattern exposure on Test Box.
The image below shows a standard test pattern exposure from the Science CCD,
mounted on the Test System. Vignetting, due to the shutter can be clearly seen.
Sci. CCD #12 Split R/O JPG image of 3s Test Pattern image.
Split R/O 3s Test Pattern image FITS data (17Mby).
Spectral Response (QE) data taken for Science CCD #12
The curve below illustrates the spectral response for the Science CCD #12,
just (Sept. 2nd) measured on the Test system.
As can be seen, the response again appears very good right across the optical band
from 350nm out to 1050nm. The data measured here appears consistent with the figures
by E2V in the data sheet for this device.
Spectral Response of E2V Science CCD#12.
E2V and RSAA Test Data for all E2V SkyMapper CCDs
The link
*E2V Test Data* references the *latest* E2V Detector Directory
- a table listing all the devices we have to date, i.e. data for the 22 science
devices, and for All 4 Engineering CCDs, the latter data all obtained on
the RSAA Test System.
Amplifier Noise measurements taken for Science CCD #12
The following data confirms the read noise meets the noise spec. for the
SkyMapper Science requirements and is similar for both output amplifiers:-
- 4.9e rms for the left/right-hand amplifiers and
This data was taken with system gain of
0.9e/adu. There is also
~1e rms of system noise included in these figures, so the devices
are performing well at the read-out rate used, approx.
250kHz.
Spectral Response Measurements for all current E2V SkyMapper CCDs
The following plot illustrates the Spectral response of all 22 Science CCDs,
shown together for comparison. Data between the points has been interpolated
by the Excel spreadsheet program.
Spectral Response of all 22 E2V CCDs currently(03/10/2006) at RSAA.
Status, September 4th, 2006
First E2V Science CCD (04484-10-02, BATCH#4)
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